A projector device is a device that collects light emitted from an optical source by means of a reflecting mirror and a lens for example, directs the light thus collected to a display element such as a liquid crystal panel to form an optical image, and projects the optical image to an outside screen or other displays via a projection lens and a projection mirror. A discharge lamp such as a high-pressure mercury lamp is generally used as the optical source of the projector device. The discharge lamp is covered with a reflector from the back and an explosion-proof glass from the front so as to have a nearly hermetically sealed form. The discharge lamp, heated to a high temperature during lighting, is set up at an appropriate temperature. However, if the discharge lamp is continuously used at temperatures exceeding the appropriate temperature, the life of the lamp will be shortened and the lamp itself might burst or be unlighted. A cooling mechanism adapted to perform forced cooling using a fan is provided in order to keep the discharge lamp at an appropriate temperature. Heat generation along with light emission causes heat convection inside the discharge lamp, such that the upper part (the upper part as viewed in the direction of gravitational force) of a spherical light-emitting part is heated to a high temperature. The upper part is cooled more strongly than the lower part, thereby keeping a temperature difference between the upper part and the lower part within a predetermined range.
The installing forms of the projector device generally include stationary installation in which the projecting device is horizontally placed on a disk and suspended installation in which the projector device is suspended from a ceiling. In the suspended installation, the projector device is attached in an upside-down manner. Other installation methods include an upward-projecting position and a downward-projecting position as the forms where an image is projected in a direction vertical to, i.e., generally perpendicular to the upper surface of a disk (in an up-down direction).
It is necessary to suitably cool a discharge lamp in any of the various installing forms described above. To meet the necessity, patent document 1 discloses a cooling device for a discharge lamp (the optical source lamp) having a plurality of cooling fans which deliver air to an optical source lamp, the cooling fans delivering the air in a direction configured to be different from each other.